Radiative Effect and Mixing Processes of a Long-Lasting Dust Event over Athens, Greece, during the COVID-19 Period

We report on a long-lasting (10 days) Saharan dust event affecting large sections of South-Eastern Europe by using a synergy of lidar, satellite, in-situ observations and model simulations over Athens, Greece. The dust measurements (11–20 May 2020), performed during the confinement period due to the...

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Main Authors: Panagiotis Kokkalis, Ourania Soupiona, Christina-Anna Papanikolaou, Romanos Foskinis, Maria Mylonaki, Stavros Solomos, Stergios Vratolis, Vasiliki Vasilatou, Eleni Kralli, Dimitra Anagnou, Alexandros Papayannis
Format: Article
Language:English
Published: MDPI AG 2021-02-01
Series:Atmosphere
Subjects:
Online Access:https://www.mdpi.com/2073-4433/12/3/318
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spelling doaj-0a2e738c42cd40b1b57a3f93591b47b32021-03-01T00:03:43ZengMDPI AGAtmosphere2073-44332021-02-011231831810.3390/atmos12030318Radiative Effect and Mixing Processes of a Long-Lasting Dust Event over Athens, Greece, during the COVID-19 PeriodPanagiotis Kokkalis0Ourania Soupiona1Christina-Anna Papanikolaou2Romanos Foskinis3Maria Mylonaki4Stavros Solomos5Stergios Vratolis6Vasiliki Vasilatou7Eleni Kralli8Dimitra Anagnou9Alexandros Papayannis10Physics Department, Kuwait University, Safat 13060, KuwaitLaser Remote Sensing Unit, Department of Physics, National and Technical University of Athens, 15780 Zografou, GreeceLaser Remote Sensing Unit, Department of Physics, National and Technical University of Athens, 15780 Zografou, GreeceLaser Remote Sensing Unit, Department of Physics, National and Technical University of Athens, 15780 Zografou, GreeceLaser Remote Sensing Unit, Department of Physics, National and Technical University of Athens, 15780 Zografou, GreeceResearch Centre for Atmospheric Physics and Climatology, Academy of Athens, 10680 Athens, GreeceEnvironmental Radioactivity Laboratory (ERL), Institute of Nuclear & Radiological Sciences & Technology, Energy & Safety, National Centre of Scientific Research ‘‘Demokritos’’, 15310 Attiki, GreeceEnvironmental Radioactivity Laboratory (ERL), Institute of Nuclear & Radiological Sciences & Technology, Energy & Safety, National Centre of Scientific Research ‘‘Demokritos’’, 15310 Attiki, GreecePhysics Department, Kuwait University, Safat 13060, KuwaitPhysics Department, Kuwait University, Safat 13060, KuwaitPhysics Department, Kuwait University, Safat 13060, KuwaitWe report on a long-lasting (10 days) Saharan dust event affecting large sections of South-Eastern Europe by using a synergy of lidar, satellite, in-situ observations and model simulations over Athens, Greece. The dust measurements (11–20 May 2020), performed during the confinement period due to the COVID-19 pandemic, revealed interesting features of the aerosol dust properties in the absence of important air pollution sources over the European continent. During the event, moderate aerosol optical depth (AOD) values (0.3–0.4) were observed inside the dust layer by the ground-based lidar measurements (at 532 nm). Vertical profiles of the lidar ratio and the particle linear depolarization ratio (at 355 nm) showed mean layer values of the order of 47 ± 9 sr and 28 ± 5%, respectively, revealing the coarse non-spherical mode of the probed plume. The values reported here are very close to pure dust measurements performed during dedicated campaigns in the African continent. By utilizing Libradtran simulations for two scenarios (one for typical midlatitude atmospheric conditions and one having reduced atmospheric pollutants due to COVID-19 restrictions, both affected by a free tropospheric dust layer), we revealed negligible differences in terms of radiative effect, of the order of +2.6% (SW<sub>BOA</sub>, cooling behavior) and +1.9% (LW<sub>BOA</sub>, heating behavior). Moreover, the net heating rate (HR) at the bottom of the atmosphere (BOA) was equal to +0.156 K/d and equal to +2.543 K/d within 1–6 km due to the presence of the dust layer at that height. On the contrary, the reduction in atmospheric pollutants could lead to a negative HR (−0.036 K/d) at the bottom of the atmosphere (BOA) if dust aerosols were absent, while typical atmospheric conditions are estimated to have an almost zero net HR value (+0.006 K/d). The NMMB-BSC forecast model provided the dust mass concentration over Athens, while the air mass advection from the African to the European continent was simulated by the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model.https://www.mdpi.com/2073-4433/12/3/318lidaraerosolsdust eventCOVID-19 lockdownradiative forcingAthens
collection DOAJ
language English
format Article
sources DOAJ
author Panagiotis Kokkalis
Ourania Soupiona
Christina-Anna Papanikolaou
Romanos Foskinis
Maria Mylonaki
Stavros Solomos
Stergios Vratolis
Vasiliki Vasilatou
Eleni Kralli
Dimitra Anagnou
Alexandros Papayannis
spellingShingle Panagiotis Kokkalis
Ourania Soupiona
Christina-Anna Papanikolaou
Romanos Foskinis
Maria Mylonaki
Stavros Solomos
Stergios Vratolis
Vasiliki Vasilatou
Eleni Kralli
Dimitra Anagnou
Alexandros Papayannis
Radiative Effect and Mixing Processes of a Long-Lasting Dust Event over Athens, Greece, during the COVID-19 Period
Atmosphere
lidar
aerosols
dust event
COVID-19 lockdown
radiative forcing
Athens
author_facet Panagiotis Kokkalis
Ourania Soupiona
Christina-Anna Papanikolaou
Romanos Foskinis
Maria Mylonaki
Stavros Solomos
Stergios Vratolis
Vasiliki Vasilatou
Eleni Kralli
Dimitra Anagnou
Alexandros Papayannis
author_sort Panagiotis Kokkalis
title Radiative Effect and Mixing Processes of a Long-Lasting Dust Event over Athens, Greece, during the COVID-19 Period
title_short Radiative Effect and Mixing Processes of a Long-Lasting Dust Event over Athens, Greece, during the COVID-19 Period
title_full Radiative Effect and Mixing Processes of a Long-Lasting Dust Event over Athens, Greece, during the COVID-19 Period
title_fullStr Radiative Effect and Mixing Processes of a Long-Lasting Dust Event over Athens, Greece, during the COVID-19 Period
title_full_unstemmed Radiative Effect and Mixing Processes of a Long-Lasting Dust Event over Athens, Greece, during the COVID-19 Period
title_sort radiative effect and mixing processes of a long-lasting dust event over athens, greece, during the covid-19 period
publisher MDPI AG
series Atmosphere
issn 2073-4433
publishDate 2021-02-01
description We report on a long-lasting (10 days) Saharan dust event affecting large sections of South-Eastern Europe by using a synergy of lidar, satellite, in-situ observations and model simulations over Athens, Greece. The dust measurements (11–20 May 2020), performed during the confinement period due to the COVID-19 pandemic, revealed interesting features of the aerosol dust properties in the absence of important air pollution sources over the European continent. During the event, moderate aerosol optical depth (AOD) values (0.3–0.4) were observed inside the dust layer by the ground-based lidar measurements (at 532 nm). Vertical profiles of the lidar ratio and the particle linear depolarization ratio (at 355 nm) showed mean layer values of the order of 47 ± 9 sr and 28 ± 5%, respectively, revealing the coarse non-spherical mode of the probed plume. The values reported here are very close to pure dust measurements performed during dedicated campaigns in the African continent. By utilizing Libradtran simulations for two scenarios (one for typical midlatitude atmospheric conditions and one having reduced atmospheric pollutants due to COVID-19 restrictions, both affected by a free tropospheric dust layer), we revealed negligible differences in terms of radiative effect, of the order of +2.6% (SW<sub>BOA</sub>, cooling behavior) and +1.9% (LW<sub>BOA</sub>, heating behavior). Moreover, the net heating rate (HR) at the bottom of the atmosphere (BOA) was equal to +0.156 K/d and equal to +2.543 K/d within 1–6 km due to the presence of the dust layer at that height. On the contrary, the reduction in atmospheric pollutants could lead to a negative HR (−0.036 K/d) at the bottom of the atmosphere (BOA) if dust aerosols were absent, while typical atmospheric conditions are estimated to have an almost zero net HR value (+0.006 K/d). The NMMB-BSC forecast model provided the dust mass concentration over Athens, while the air mass advection from the African to the European continent was simulated by the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model.
topic lidar
aerosols
dust event
COVID-19 lockdown
radiative forcing
Athens
url https://www.mdpi.com/2073-4433/12/3/318
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